There are described in Japanese publication 81-103192 (Chem. Abstract, Selects-Antitumor Agents, Issue 13, (1982), page 10, 96:193435j) stilbenediamine platinum-complexes of the following formula ##STR2## In the formula the group R.sub.1 and R.sub.2 are halogen, NO.sub.3, SO.sub.4, OH, or glucuronic acid groups. An antitumor activity is stated for these compounds.